The present invention relates to an adjustable tap extension for use with numerical control (N.C.) manufacturing machines. The N.C. machines are complex, computer operated, machines capable of automatically performing several machining functions. Drilling, reaming, milling, tapping, etc. are a few examples of operations the machine can perform. The N.C. machine can produce finished parts from raw material automatically. The material, such as steel, is simply fastened to the machine table and the machine is started. The finished part is ready in a few minutes. This saves countless hours of machinists' time and considerable expense when mass production is involved.
The N.C. machine is controlled by a magnetic tape. Each machine function is controlled by the program recorded on the tape. It is fairly expensive and time consuming to perfect the recorded program. The machines are therefore best suited to mass production. The time and manufacturing expense saved would then offset the initial set up cost of proving the recorded program.
The present tap holders and extensions for use with N.C. machines are not adjustable for length. Therefore once the tap is dull it cannot be resharpened and reused. This is because the tap is shortened when resharpened. Since the program was recorded for the original tool length, a resharpened tap would not be compatible with the proven program. An adjustable tap extension would then be extremely desirable. This would allow the use of resharpened taps with the original program. Since the larger sized taps (over 1/2 inch) are fairly expensive, a significant tool savings could also be realized.